Device for lapping and grinding balls



y 1966 s. MESSERSCHMIDT 3,250,042

DEVICE FOR LAPPING AND GRINDING BALLS Filed May 22, 1964 2 Sheets-Sheet 1 S. MESSERSCHMIDT DEVICE FOR LAPPING AND GRINDING BALLS May 10, 1966 2 Sheets-Sheet 2 Filed May 22, 1964 United States Patent Office 3,250,042 Patented May 10, 1966 3,250,042 DEVICE FOR LAIPING AND GRINDING BALLS Sebastian Messerschmidt, Altstadstrasse 5, Schweinfurt, Germany I Filed May 22, 1964, Ser. No. 369,472 Claims priority, applicatirsn; Germany, May31, 1963,

8 Claims. (51. 51-116 The invention relates to a device for lapping and grindrng balls with a magazine rotating in a substantially horizontal plane, which repeatedly feeds the continuous stream of balls to a ball inlet leading to the lapping wheels.

In the manutacture of balls, the endeavor to achieve a rational mode of working is not directed solely to obtaining greater precision as regards measurement and shape, but also to saving manual labour, that is as tar as possible automation of the lapping operation.

An important step in this direction is the use of an annular magazine with systematic continuous passage of the balls. It is true then that trouble can still occur through varying of the addition of oil and grinding agent or through irregularities in the leading-E of the grinding dust. Thus stoppages can then occur at the ball inlet if the balls are not reliably gripped and entrained by the lapping wheels. This generally leads to serious trouble and possibly also to a considerable amount of rejected material.

The object of the invention is therefore to device and establish the conditions for a substantially automatic satisfactory method for lapping and grinding the balls, in order to be able to immediately detect and eliminate disturbances with all the detrimental effects resulting therefrom.

With this object in view it is proposed according to the invention to arrange an arm making contact with the layer of balls in the vicinity of the ball inlet to the lapping wheel and connected with a signal, final control element or the like which becomes operative according to the position of the arm.v

The control or supervision therefore takes place directly at the danger point itself, so that any irregularity in the operation can already be detected at the moment it actually occurs.

In the simplest case it is suflicient to notify the disturbance by an opticahacoustic or some other similar signal which attracts the attention of the operator so that he can take the necessary action.

However, it is quite possible to exert a control function on the working operation, which in extreme cases leads to the stopping of the machine.

This embodiment of the invention also takes into consideration the fact that a disturbance in the circulation of the balls first becomes apparent-directly at the inlet to the lapping wheel. By radialarrangement, however, a sufliciently large field of traverse is obtained for the feeler arm.

It has been found particularly advantageous to provide stops limiting the field of traverse of the feeler arm and to make these stops adjustable according to the actual working conditions. The field of traverse of the feeler 'arm can be adjusted in a simple manner according to the size of the balls actually being worked.

It is also within the scope of the invention to make the arrangement so that the feeler arm in at least two positions cooperates with one of two parallel-connected switch elements of the regulating, signalling or other circuit, whereby the switch element is normally closed when the swivel arm is in the upper swivel position and normally opened when it is in the lower swivel position.

As a result the feeler arm, which as the ball bed rises produces a signal or the like by opening a switch and in descending with the level of the ball bed after rectifying the disturbance and clearing the ball stoppage, first again closes the switch opened on account of the disturbance, whereby however normal working is only restored when the second switch is also actuated after the feeler arm has descended.

The contact surface of the feeler arm resting on the ball bed is preferably provided with a coating of wearresisting material. For this purpose leather and also a large range of plastics come into question because these not only have a long life but prevent damage to the balls.

In another embodiment of the invention, a speed regulator for the magazine drive can be coordinated to the feeler arm. Thus, for example, any further rise in the level of the ball bed in the region of the ball inlet to the lapping wheels is counteracted by a reduction in the speed at which the magazine rotates. It is also possible to connect up behind the speed regulator a switch element which cuts out the drive of the magazine and only responds when the ball accummulation continues to increase in spite of the decrease in the speed of rotation of the magazine.

Finally, it likewise comes within the scope of the invention to coordinate to the feeler arm .a regulator for the addition of oil and/or abrasive, which exerts a controlling effect in the event of any disturbance and reestablishes the optimal friction conditions between the lapping wheels.

Further features, details and advantages of the invention will become apparent from the following description of a preferred embodiment illustrated by way of example in the accompanying drawings, in which FIG. 1 is a vertical section through a ball inlet and the magazine of a lapping device, taken on line II of FIG. 2;

FIG. 2 a broken-open top plan view of the device illustrated in FIG. 1;

FIG. 3 a section on line IIIIII of FIG. 2, and

FIG. 4 a simplified circuit diagram of the device.

The lapping device operates with two lapping wheels which rotate plane parallel to each other abouta vertical axis, the lower of these wheels being designated by 1 and having a series of concentric grooves 2 in which the balls 3 are guided. Facing the rotating lower lapping wheel 1 travelling in the direction of the arrow 4 is the upper stationary lapping wheel 5.

The lapping wheels 1, 5 are arranged eccentrically within an annular magazine 6 surrounding them and forming a continuous groove extending in the direction of the arrow 7 and formed by the bottom surface 8 and the two side walls 9 and 10.

The ball inlet 11 consists of a sector-shaped aperture in the upper lapping wheel 5 and projecting into this aperture 11 is a shoe designated by 12 the foot 13 of which merges in the form of an are into the outer boundary wall 9 of the magazine 6 while the other end 14 rests on the lapping wheel holder. This shoe 12 extends substantially radially across the magazine 6 and through the ball inlet 11 so that the balls travelling in the magazine 6 in the direction of the arrow 15 are deflected from their circular path and, as indicated by the arrows, fed between the lapping wheels 1 and 5. The rear side of the shoe 12 is similarly constructed so that it is capable of guiding the stream of balls passing out from between the lapping wheels into the groove of the magazine 6, as indicated by the arrow 7.

On the foot 13 of the shoe 12 a bearing 16 is provided for a substantially tangential shaft 17 on the free end of which a feeler arm 18 projecting into the ball inlet 11 is fixed by means of a knurl-head screw 19 or the like. This feeler arm 18 terminates in a plate 20 which, as shown in FIG. 1, rests on the balls within the ball inlet 11. This.

plate 20 preferably has on its bearing surface a wearresisting coating of plastic substance or leather, which however is not shown on the drawings.

Two adjustable stops 21 are provided in the bearing 16 and limit the swivel range of the feeler arm 18 in both directions, as indicated by the arrow 22. The fork 23 of the feeler arm 18 carries two adjustable contact elements 24 which act on a switching lever 25 mounted at 26 in tr swivel housing designated as a whole by 26. Through the intermediary of contacts 28this switching lever cooperates with contacts 29 and 30 of parallel-connected switches 31 and 32.

In the circuit diagram illustrated in FIG. 4 the driving motor for the magazine 6 is designated by 33. In the feed circuit 34 leading to the motor, apart from the main switch 35, another switch 37 controlled by a relay 36 connected up behind the two switches 31 and 32, is provided. The relay 36 is series-connected with the two switches 31 and 32. It operates two other switches 38 and 39, the switch 38 being connected in series wit-h the switch 32 whereas as the switch 39 is provided in the circuit 40 in which the signal lamp 41 is located.

' If for any reason the ball bed in the ball inlet 11 rises above a certain lever, as indicated at 42 in FIG. 1, the feeler arm 18 will swing in the direction of the arrow 43 about the shaft 17. One of the contact bolts 24 then strikes against the switching lever 25, as shown in FIG. 3, so that one of the contacts, for example the contact 28, bears against the contact 30, thereby opening a switch 32 which is normally closed. As the parallel connected switch 31 is normally open the relay 36 is deprived of current and the switch 37 in the circuit 34 leading to the driving motor 33 of the magazine 3 opens. At the same time the switch 38 drops but on the other hand the switch 39 closes the feed circuit to the signalling element 41 in the circuit 40. The excessive rise of the ball bed 42 will thus be indicated to the operator so that he can take the necessary steps to remove the disturbance. When this has been done or if the ball accumulation 42 is again reduced automatically, the feeler arm 18 again drops in the direction counter to the arrow 43, whereby the switch 32 is closed automatically. The relay 46 does not however yet receive current because the switches 38 and 31 are still open. Only when the feeler arm 18 swings below the normal level of the ball bed in the ball inlet 11 does the contact 28 of the switching lever 25 come into contact with the contact 29 of the switch 31 and consequentlycloses this as long as these contacts 28 and 29 are in touch. The relay 36 is then tensioned and simultaneously closes the switch 37 in the feed circuit 34 leading to the driving motor 33 for the magazine 6 and also the switch 38 which is in series with the switch 32. On the other hand the switch 39 is opened so that the signalling device 41 is deprived of current. Only when the ball bed in the ball inlet 11 again reaches its normal level is the connection between the contacts 28 and 29 severed and consequently the switch 31 opened. In this stage the relay is under current through the normally closed switch 32.

It is evident that the invention is not confined to the embodiment described above and illustrated in the accompanying drawings and that numerous modifications are possible without departing from the fundamental idea of the invention. Thus, the circuit diagram merely shows a particularly simple case for regulating the motor 33 for the magazine 6. It is, however, quite possible to provide a stepped or infinite regulation for the motor 33. On the other hand switching elements effecting the dosing of the oil addition and the abrasive material addition can also be provided in a similar manner.

What I claim is:

1. Device for lapping and grinding balls, comprising an annular magazine rotating in a substantially horizontal plane, two superposed lapping wheels arranged within said annular magazine, a continuous stream of balls being continuously fed from the magazine through a ball inlet leading between the two lapping wheels, a feeler arm arranged in the region of the ball inlet and in contact with'the layer of balls in the magazine, and switching elements for signalling, regulating and other similar purposes connected with said feeler arm and actuated thereby according to its position.

2. Device according to claim 1, wherein the feeler arm engages substantially radially in the ball inlet and is mounted to swivel about an axis substantially tangential thereto. I

3. Device according to claim 2, wherein the swivel range of the feeler arm is limited by adjustable stops.

4.'Device according to claim 3, wherein the feeler arm in at least two diiferent positions cooperates with one of two parallel connected switching elements of the regulating, signalling or other circuit, whereby the switching element corresponding to the upper swivel position is normally closed and the switching element corresponding to the lower swivel position is normally open- 5. Apparatus according to claim 4, wherein at least one adjustable switching lever is coordinated to the feeler arm and in turn acts on the switching elements of the regulating, signalling or other circuit.

6. Device according to claim 1, wherein the contacting surface of the feeler arm has a wear-resisting coating.

7. Apparatus according to claim 1, wherein a speed regulator for the magazine drive is coordinated to the feeler arm.

8. Device according to claim 1, wherein a regulator for dosing the oil and abrasive additions is coordinated to the feeler arm.

References Cited by the Examiner UNITED STATES PATENTS 2,964,886 12/1960 Messerschmidt 51-289 X ROBERT C. RIORDON, Primary Examiner.

LEONARD S. SELMAN, Examiner. 

1. DEVICE FOR LAPPING AND GRINDING BALLS, COMPRISING AN ANNULAR MAGAZINE ROTATING IN A SUBSTANTIALLY HORIZONTAL PLANE, TWO SUPERPOSED LAPPING WHEELS ARRANGED WITHIN SAID ANNULAR MAGAZINE, A CONTINUOUS STREAM TO BALLS BEING CONTINUOUSLY FED FROM THE MAGAZINE THROUGH A BALL INLET LEADING BETWEEN THE TWO LAPPING WHEELS, A FEELER ARM ARRANGED IN THE REGION OF THE BALL INLET AND IN CONTACT WITH THE LAYER OF BALLS IN THE MAGAZINE, AND SWITCHING ELEMENTS FOR SIGNALLING, REGULATING AND OTHER SIMILAR PURPOSES CONNECTED WITH SAID FEELER ARM AND ACTUATED THEREBY ACCORDING TO ITS POSITION. 